Operation is not valid due to the current state of the object

Question

We are working with the System.Transactions for transaction control. An error is happening when confirming a transaction. Even without having changed any information. The user opens a register and does not modify any information, press the Change button and generates the error. Is not processed any UPDATE, DELETE, INSERT. Only queries. Below is the error details:
Data base: Oracle 11g
Application Server: Windows 2003 64 bits. Client 11g 32 bits and 64 bits
Location: System.Transactions
StackTrace:
at System.Transactions.TransactionState.ChangeStatePromotedCommitted(InternalTransaction tx)
at System.Transactions.DurableEnlistmentDelegated.Committed(InternalEnlistment enlistment)
at System.Transactions.SinglePhaseEnlistment.Committed()
at Oracle.DataAccess.Client.PromotableTxnMgr.SinglePhaseCommit(SinglePhaseEnlistment spe)
at System.Transactions.TransactionStateDelegatedCommitting.EnterState(InternalTransaction tx)
at System.Transactions.TransactionStateDelegated.BeginCommit(InternalTransaction tx, Boolean asyncCommit, AsyncCallback asyncCallback, Object asyncState)
at System.Transactions.CommittableTransaction.Commit()
at System.Transactions.TransactionScope.InternalDispose()
at System.Transactions.TransactionScope.Dispose()
at FPw.InfraEstrutura.DataAccess.FPwTransacao.Dispose()
at LG.FPw_Cad.ServicoMapeador.Servicos.FichaCad.Update(Int32 lUserId, Int32 lMatFunc, LGVariant avRegFun, LGVariant avRegATF, Double dSalario, Boolean bConsiste)

Answer 1

What I meant is that it's done any kind of alteration of the tables involved, because the user does not change any of your information on the screen.
The problem happens on a client and does not happen in our test environment.
The version of Oracle.DataAccess both 32-bit and 64 bit is 2.112.1.0.
What is the code in the following summary:
1) Is created transactional context:
Dim TxOptions As New TransactionOptions
Dim OpcaoDeEscopo As TransactionScopeOption
Dim Transacao As System.Transactions.TransactionScope
TxOptions.IsolationLevel = Transactions.IsolationLevel.ReadCommitted
OpcaoDeEscopo = TransactionScopeOption.Required
Transacao = New TransactionScope(opcaoDeEscopo, TxOptions, EnterpriseServicesInteropOption.Full)
2) From this point are open connections are made and query commands to the database.
Are opened and closed connections to the database.
3) At the time of effecting the transaction Dispose of the error happens:
Transacao.Dispose
Note: Our way of working has its own peculiarities, the connection pool is always disabled: ";Pooling = false". It is inserted directly in the connection string. We need to do this because the pool had memory problems turned prey.
Therefore the process of opening and closing connections, you can leave the system slow. So to avoid open connections within the transactional context, in some cases we enforce the transaction enlist. As follows:
Dim TransacaoCorrente As ITransaction = CType(ContextUtil.Transaction, ITransaction)
Conexao.EnlistDistributedTransaction(TransacaoCorrente)
Can you help us?
Edited by: 893128 on Oct 25, 2011 9:24 AM